Tracks are used as supports for conveyor slats or the stair members of moving stairway. Rollers of the conveyor slat or of the stair member move over the track surface which serves as a race. The track should provide a smooth, free of dynamic impacts, movement of the rollers over the race, when passing from a horizontal section of the track to an inclined one.
Known in the art are vertically adjustable moving stairway tracks, which comprise straight-line horizontal and inclined sections hinged to each other. An obtuse angle is formed in moving stairways using such tracks in the point of connection of the horizontal and inclined sections of their races. As a result, dynamic impacts occur, when the stair rollers move from the horizontal section onto the inclined one, which causes an increased wear of the rollers and of the race; it can also cause falling of the people being transported.
This deficiency is eliminated in the vertically adjustable moving stairway track (c.f. USSR Inventor's Certificate No. 523020) comprising a horizontal and an inclined straight-line sections coupled with a curvilinear section. The curvilinear section of the track is formed by two elements having the same radius of curvature. One of the elements has an U-shaped cross-section and is rigidly fastened to the horizontal section of the track. The other element is rigidly attached to the inclined section of the track and is slidablay mounted within the U-shaped element so that it can move longitudinally inside said U-shaped element. Thus, the curvilinear section of the track has a telescopic construction.
The upper surfaces of said elements are disposed at the same level and form, in combination, the race of the curvilinear section of the track. When the elevation height of the track is varied, the curvilinear section elements slide out from one another, whereby the length of the curvilinear section increases, while its radius of curvature remains constant.
Such a track has a limited range of variation in height because of the limited change in the length of the curvilinear section. The telescopic construction of the curvilinear section makes it possible to increase its length by not more than a factor of I.8. Moreover, any misalignment of the inclined and horizontal sections of the track causes jamming of the curvilinear section elements, thus preventing any change in the track elevation height. This reveals low reliability of this track in service.
The width of the race along the curvilinear section of the track varies with the variation of the height of the track. As a result, when moving over the curvilinear section of the track, the stair rollers would bear upon the track, at certain instants only by a portion of their width. Moreover, it is the very curvilinear section where the load on the rollers is at the maximum. All this results in an increased wear of the stair rollers.